WO2017091319A1

WO2017091319A1 - Pneumatic tires with compositionally similar components

Info

Publication number: WO2017091319A1
Application number: PCT/US2016/058993
Authority: WO
Inventors: Kent D. Weatherwax; Maryangel G. Dunlavy; Amy M. Randall; Jon I. Stuckey; Ross W. WIDENOR
Original assignee: Bridgestone Americas Tire Operations, Llc
Priority date: 2015-11-23
Filing date: 2016-10-27
Publication date: 2017-06-01

Abstract

Provided is a pneumatic tire comprising a carcass including a skim rubber, a pair of sidewalls, a pair of bead bundles, a pair of abrasion strips, a tread, and an innerliner, where the skim rubber, the sidewalls, the abrasion strips, and the innerliner are prepared from a vulcanizable composition including a rubber component that includes a polychloroprene-based elastomer.

Description

PNEUMATIC TIRES WITH COMPOSITIONALLY SIMILAR COMPONENTS

FIELD OF THE INVENTION

[0001] Embodiments of the present invention relate to pneumatic tires having multiple components that are compositionally similar. In particular embodiments, the pneumatic tires have compositionally similar sidewalls, abrasion strips, skim rubber, and optionally innerliner.

BACKGROUND OF THE INVENTION

[0002] Pneumatic tires are constructed from multiple components that are co-cured to provide a multicomponent composite structure. Each component offers a particular attribute that contributes to the overall usefulness of the pneumatic tire. For example, the various tire components include a body, sidewalls, tread package, innerliner, belt package, bead bundles, bead fillers, and abrasion gum strips.

[0003] The desired attributes of the various tire components derive, in large part, from the composition used to fabricate the respective components. For example, the carcass includes a plurality of body plies that provide a framework for the tire, which framework is formed by a combination of reinforcing fabric cords and a skim rubber operating as a matrix for the cords. Proper adhesion between the reinforcing cords and the skim rubber is an important attribute, as is the flexibility and low elasticity of the skim rubber. As a skilled person will appreciate, adhesion to the cord can be achieved through both the selection of the rubber as well as rubber additives such as adhesion promoters.

[0004] The sidewall helps to protect the body plies from abrasion, impact and flex fatigue. The sidewalls also transmit steering, driving, and braking forces from the wheel to the tread, and therefore the sidewalls are formulated to yield a rubber component with relatively high modulus. And, the sidewalls, which are exposed to air and sunlight, are formulated to provide resistance to light and ozone degradation.

[0005] The innerliner seals the air chamber to resist inflation loss. Accordingly, the innerliner is formulated to have low oxygen permeability. Additionally, in order to provide low rolling resistance and reduced overall weight of the tire, the innerliner is typically fabricated as a relatively thin layer of rubber. As a result, the innerliner is susceptible to cracking, especially since the innerliner undergoes flex fatigue during use. The innerliner is also specifically formulated to provide resistance to crack growth under dynamic stresses.

[0006] Abrasion gum strips provide a layer of rubber between the body plies and the wheel rim to thereby provide resistance against chafing while enabling an airtight seal between the tire and rim.

[0007] The skilled person also appreciates the fact that many of the desirable tire attributes are mutually incompatible. That is, when a tire component is formulated to achieve a particular attribute, other desirable attributes may be lost or compromised. Additionally, practical considerations, such as raw material costs, influence the use of certain specialized ingredients, such as adhesion promoters or anti-ozidants, only in those tire components where their influence can be realized. In view of this, tire manufacturers employ specifically formulated compositions for each of the various tire components.

SUMMARY OF THE INVENTION

[0008] One or more embodiments of the present invention provide a pneumatic tire comprising a carcass including a skim rubber, a pair of sidewalls, a pair of bead bundles, a pair of abrasion strips, and a tread, where the skim rubber, the sidewalls, and the abrasion strips are compositionally similar.

[0009] Other embodiments of the present invention provide a pneumatic tire comprising a carcass including a skim rubber, a pair of sidewalls, a pair of bead bundles, a pair of abrasion strips, and a tread, where the skim rubber, the sidewalls, and the abrasion strips are prepared from a single vulcanizable composition that includes a rubber component including a polychloroprene-based rubber.

[0010] Still other embodiments of the present invention provide a method for preparing a pneumatic tire, the method comprising the steps of preparing a vulcanizable composition including a rubber component that includes polychloroprene and natural rubber, forming the vulcanizable composition into a carcass, a pair of sidewalls, and a pair of abrasion strips, building a green tire from by employing the carcass, the pair of sidewalls, and the pair of abrasion strips, and curing the green tire to form the pneumatic tire. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Fig. 1 is a cross-sectional view of a portion of a pneumatic tire made according to one or more aspects of the present invention.

[0012] Fig. 2 is a cross-sectional view of a portion of a tire carcass made according to one or more aspects of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

[0013] Embodiments of the present invention are based, at least in part, on the discovery of a pneumatic tire wherein the skim rubber, sidewalls, abrasion gum strips, and optionally the innerliner are compositionally similar. Stated another way, these tire components are prepared from a particular vulcanizable composition that has unexpectedly been found to provide an advantageous overall balance of properties that contributes to a technologically useful tire even though the vulcanizable composition is used to prepare highly distinct tire components. Thus, despite conventional wisdom suggesting the necessity to employ highly distinct vulcanizable compositions for various tire components, technologically useful tires can be prepared by using the vulcanizable composition of this invention to fabricate these tire components. It is believed that the ability to produce these various components from a single or a substantially similar composition derives, at least in part, from the use of polychloroprene within the rubber formulation. Accordingly, embodiments of the invention are directed toward tires wherein the skim rubber, sidewalls, abrasion strips, and optionally innerliner are prepared from compositionally similar vulcanizable compositions that include polychloroprene.

COMPOSITIONAL SIMILARITY

[0014] As suggested above, advantages associated with the present invention derive from the compositional similarity of the identified tire components. This similarity may be defined based upon the weight of the various constituents within two or more compositions (i.e. compositions of the tire components) being compared. For example, in one or more embodiments, compositionally similar components include the same constituents at a weight loading that does not vary by more than 5 percent, in other embodiments by not more than 3 percent, and in other embodiments by not more than one percent. In one or more embodiments, compositionally similar tire components have substantially the same composition, which refers to the fact that there is no appreciable difference between the compositions of the various components. In particular embodiments, the compositions of the identified components is exactly the same. Stated another way, the identified components are prepared from a single vulcanizable composition.

TIRE CONSTRUCTION

[0015] In one or more embodiments, the tires and tire components of the present invention can be described with reference to Fig. 1, which shows pneumatic tire 10 including a tread portion 12, a belt package 14, a pair of sidewalls 16, 16', an innerliner 18, a pair of axially spaced bead bundles 20, 20', a pair of abrasion strips 26, 26' (which may also be referred to as chafers 26, 26'), and a carcass 28 (which may be referred to as body 28). Carcass 28 is generally toroidal in shape and extends from first bead 20 to second bead 20'. As generally shown in Fig. 2, carcass 28 includes one or more carcass plies 30, 30' (which may be referred to as body plies 30, 30') that include reinforcing cords 32, 32'calendared with a rubber, which is typically referred to as a skim rubber, that forms a matrix 34, 34' around cords 32, 32'.

VULCANIZABLE COMPOSITION

[0016] As indicated above, the pneumatic tires of the present invention include a compositionally similar skim rubber, sidewalls, abrasion strips, and optionally innerliner. In accordance with the present invention, these tire components derive from one or more vulcanizable compositions that include a polychloroprene-containing rubber component, filler, plasticizer, and curative. In one or more embodiments, the rubber component may include other vulcanizable elastomers. Also, in one or more embodiments, the vulcanizable compositions may include other constituents including, but not limited to, cure activators, cure accelerators, oils, resins, other plasticizers, pigments, cord adhesion promotors, fatty acids, zinc oxide, magnesium oxide, and peptizing agents.

POLYCHLOROPRENE

[0017] In one or more embodiments, polychloroprene-containing rubber includes those polymers that derive from the polymerization of halogenated dienes and optionally monomer copolymerizable therewith. For example, halogenated dienes include 2-chloro- 1,3-butadiene, which is also known as chloroprene. Monomer copolymerizable with chloroprene includes, but is not limited to, 1,3-butadiene and 2,3-dichloro-l,3-butadiene. For purposes of this description, rubbers deriving exclusively from the polymerization of chloroprene may be referred to as polychloroprene homopolymers, and polymers deriving from the copolymerization of chloroprene and monomer copolymerizable therewith may be referred to as polychloroprene copolymers. Otherwise, reference to the term polychloroprene or polychloroprene-containing should be understood to include both homopolymers and copolymers as defined herein. As the skilled person appreciated, polychloroprene is often referred to as neoprene, and therefore neoprene and polychloroprene may be used interchangeably.

[0018] In one or more embodiments, polychloroprene (polychloroprene homopolymer and copolymers) employed in the practice of this invention may be characterized by a Mooney viscosity (ML1+4 at 100°C) of at least 25, in other embodiments at least 40, in other embodiments at least 60, in other embodiments at least 80, and in other embodiments at least 100. In these or other embodiments, the polychloroprene may be characterized by a Mooney viscosity (ML1+4 at 100°C) of less than 150, in other embodiments less than 130, in other embodiments less than 110 in other embodiments less than 80, in other embodiments less than 60, and in other embodiments less than 50. In particular embodiments, the polychloroprene may be characterized by a Mooney viscosity (ML1+4 at 100°C) of from about 100 to about 120, and in other embodiments from about 41 to about 51.

[0019] In one or more embodiments, blends of distinct polychloroprene (i.e. polychloroprene homopolymers or copolymers) may be employed to achieve a desirable balance of properties. These distinctions may be based upon comonomer content and/or viscosity of the polymers.

[0020] Particularly useful examples of desirable polychloroprene are available from DuPont Performance Elastomers (Wilmington, DE) under the Neoprene™ "WD", "WRT", and "G" family designations. It is believed that Neoprene™ WD and WRT are relatively crystallization-resistant. Neoprene™ G-type, and are copolymers of chloroprene and 2,3- dichloro-l,3-butadiene. Neoprene™ WD exhibits a Mooney Viscosity range (ML1+4 at 100 °C) of 100-120, while Neoprene™ WRT exhibits a Mooney Viscosity range (MLi₊₄ at 100 °C) of 41-51. OTHER ELASTOMERS

[0021] As suggested above, the rubber component of the vulcanizable compositions of this invention may include other elastomers. As a skilled person understands, the term elastomer refers to those polymers that can be vulcanized to form compositions possessing rubbery or elastomeric properties. These elastomers may include natural and synthetic rubbers. In one or more embodiments, synthetic rubbers may derive from the polymerization of conjugated diene monomer, the copolymerization of conjugated diene monomer with other monomer such as vinyl-substituted aromatic monomer, or the copolymerization of ethylene with one or more oc-olefins and optionally one or more diene monomers.

[0022] Exemplary elastomers include natural rubber, synthetic polyisoprene, polybutadiene, polyisobutylene-co-isoprene, poly(ethylene-co-propylene), poly(styrene- co-butadiene), poly(styrene-co-isoprene), poly(styrene-co-isoprene- co-butadiene), poly(isoprene- co-butadiene), poly(ethylene-co-propylene- i:o-diene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, and mixtures thereof. These elastomers can have a myriad of macromolecular structures including linear, branched, and star-shaped structures. These elastomers may also include one or more functional units, which typically include heteroatoms. In particular embodiments, the vulcanizable compositions of this invention include a blend of polychloroprene homopolymer and natural rubber.

FILLER

[0023] As suggested above, the vulcanizable composition of this invention include a filler. Useful fillers may include one or more conventional reinforcing or non-reinforcing fillers. For example, useful fillers include carbon black, silica, alumina, and silicates such as calcium, aluminum, and magnesium silicates.

[0024] In one or more embodiments, carbon blacks include furnace blacks, channel blacks, and lamp blacks. More specific examples of carbon blacks include super abrasion furnace (SAF) blacks, intermediate super abrasion furnace (ISAF) blacks, high abrasion furnace (HAF) blacks, fast extrusion furnace (FEF) blacks, fine furnace (FF) blacks, semi- reinforcing furnace (SRF) blacks, medium processing channel blacks, hard processing channel blacks, conducting channel blacks, and acetylene blacks. Representative carbon blacks useful in one or more embodiments may include those designated by ASTM D1765 as N326, N330, N339, N343, N347, N351, N358, N550, N650, N660, N762, N772, and N774.

[0025] In particular embodiments, the carbon blacks may have a surface area (EMSA)

p p

of at least 20 m /g, in other embodiments at least 35 m /g, in other embodiments at least p p

50 m /g, in other embodiments at least 60 m /g; surface area values can be determined by ASTM D-1765 using the cetyltrimethylammonium bromide (CTAB) technique. In particular embodiments, the sidewalls include carbon black filler having a surface area (EMSA) of from about 60 to about 110 m²/g. The carbon blacks may be in a pelletized form or an unpelletized flocculent form. The preferred form of carbon black may depend upon the type of mixing equipment used to mix the rubber compound.

[0026] In one or more embodiments, the filler may include silica. When silica is used as a filler, the silica may be employed in conjunction with a coupling agent. In these or other embodiments, the silica may be used in conjunction with a silica dispersing agent.

[0027] In one or more embodiments, useful silicas include, but are not limited to, precipitated amorphous silica, wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), fumed silica, calcium silicate, and the like. Other suitable fillers include aluminum silicate, magnesium silicate, and the like. In particular embodiments, the silica is a precipitated amorphous wet-processed hydrated silica. In one or more embodiments, these silicas are produced by a chemical reaction in water, from which they are precipitated as ultra-fine, spherical particles. These primary particles are believed to strongly associate into aggregates, which in turn combine less strongly into agglomerates.

[0028] Some commercially available silicas that may be used include Hi-Sil™ 215, Hi- Sil™ 233, and Hi-Sil™ 190 (PPG Industries, Inc.; Pittsburgh, Pa.). Other suppliers of commercially available silica include Grace Davison (Baltimore, Md.), Degussa Corp. (Parsippany, N.J.), Rhodia Silica Systems (Cranbury, N.J.), and J.M. Huber Corp. (Edison,

N.J.)-

[0029] In one or more embodiments, silicas may be characterized by their surface areas, which give a measure of their reinforcing character. The Brunauer, Emmet and Teller ("BET") method (described in / Am. Chem. Soc, vol. 60, p. 309 et seq.) is a recognized method for determining the surface area. The BET surface area of silica is generally less than 450 m /g. Useful ranges of surface area include from about 32 to about 400 m²/g, about 100 to about 250 m²/g, and about 150 to about 220 m²/g.

[0030] In one or more embodiments, the pH of silica may be from about 5 to about 7 or slightly over 7, or in other embodiments from about 5.5 to about 6.8.

[0031] In one or more embodiments, useful silica coupling agents include sulfur- containing silica coupling agents. Examples of sulfur-containing silica coupling agents include bis(trialkoxysilylorgano)polysulfides or mercapto-organoalkoxysilanes. Types of bis(trialkoxysilylorgano)polysulfides include bis(trialkoxysilylorgano)disulfide and bis(trialkoxysilylorgano)tetrasulfides. Exemplary silica dispersing aids include, but are not limited to an alkyl alkoxysilane, a fatty acid ester of a hydrogenated or non-hydrogenated Cs or Ce sugar, a polyoxyethylene derivative of a fatty acid ester of a hydrogenated or non- hydrogenated C5 or C₆sugar, and mixtures thereof, or a mineral or non-mineral additional filler.

CURATIVE

[0032] As suggested above, the vulcanizable compositions employed in the practice of this invention include a curative for the rubber (i.e. a material can crosslink or vulcanize the polychloroprene or other rubber). A multitude of curatives, which may also be referred to as rubber curing agents (also called vulcanizing agents), may be employed, including sulfur or peroxide-based curing systems. Curing agents are described in Kirk-Othmer, ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY, Vol. 20, pgs. 365-468, (3^RD Ed. 1982), particularly Vulcanization Agents and Auxiliary Materials, pgs. 390-402, and A.Y. Coran, Vulcanization, ENCYCLOPEDIA OF EOLYMER .SCIENCE AND ENGINEERING, (2^ND Ed. 1989), which are incorporated herein by reference. In one or more embodiments, the curative is sulfur. Examples of suitable sulfur vulcanizing agents include "rubberrmaker's" soluble sulfur; sulfur donating vulcanizing agents, such as an amine disulfide, polymeric polysulfide or sulfur olefin adducts; and insoluble polymeric sulfur. Vulcanizing agents may be used alone or in combination.

[0033] In one or more embodiments, the curative is employed in combination with a cure accelerator. In one or more embodiments, accelerators are used to control the time and/or temperature required for vulcanization and to improve properties of the vulcanizate. Examples of accelerators include thiazol vulcanization accelerators, such as 2- mercaptobenzothiazol, dibenzothiazyl disulfide, N-cyclohexyl-2-benzothiazyl-sulfenamide (CBS), and the like, and guanidine vulcanization accelerators, such as diphenylguanidine (DPG) and the like.

PLASTICIZER

[0034] As suggested above, the vulcanizable compositions of this invention include a plasticizer. A multitude of plasticizer, which may also be referred to as plasticizing compounds, may be employed within the vulcanizable compositions of the invention. Useful plasticizers include hydrocarbon oils, ester plasticizers, polymeric plasticizers, and chlorinated hydrocarbons. Useful hydrocarbon oils include, but are not limited to, aromatic oils, paraffinic oils, naphthenic oils, vegetable oils other than castor oils, low PCA oils including MES, TDAE, and SRAE, and heavy naphthenic oils. Useful ester plasticizers include sebacates, adipates, phthalates, phosphates, and oleates. In particular embodiments, the ester plasticizer is di-2-ethyl-hexylsebacate. Useful polymeric plasticizers include coumarone-indine resins.

[0035] In particular embodiments, the plasticizers are those that plasticize the polychloroprene. In particular embodiments, one or more plasticizers may be used for the polychloroprene and one or more may be used for the other rubbers. Where a plasticizer is used that is specifically targeted to plasticize the polychloroprene, reference may be made to polychloroprene-specific plasticizer. Examples of these plasticizers include, but are not limited to, ester plasticizers such as sebacates, adipates, phthalates, phosphates, and oleates.

ANTIDEGRADANTS

[0036] In one or more embodiments, vulcanizable composition of this invention include antidegradants. As the skilled person will appreciate, antidegradants may include antioxidants and antiozonants. In one or more embodiments, useful antioxidants include substituted phenols, diphenyl amine-acetone reaction products, 2,2,2 -trimethyl- 1,2- dihydroquinoline polymer (TMQ), and tri(nonophenyl)phosphite. In one or more embodiments, useful antiozonants include amines such as N,N-disubstituted-p-phenylene diamines. These diamines may include both symmetrical and asymmetrical compounds. Useful symmetrical diamines include N,N-dialkyl-p-phenylene diamine. Useful asymmetrical diamines include N-alkyl, N'-aryl-p-phenylene diamines such as N-(l,3- dimethylbutyl)-N'-phenyl— p-phenylene diamine (6PPD) and N-isopropyl-N'-phenyl-p- phenylene diamine.

[0037] In one or more embodiments, the antidegradants may include waxes. Useful waxes include paraffinic waxes and microcrystalline waxes. Useful waxes include those having a molecular weight of from about 100 to about 1000 g/mole, in other embodiments from about 300 to about 800 g/mole, and in other embodiments from about 400 to about 700 g/mole.

CORD ADHESION PROMOTORS

[0038] In one or more embodiments, the vulcanizable compositions may include one or more adhesion promoters. As the skilled person will appreciate, these adhesion promotors promote and/or maintain adhesion between the fabric cord and the rubber matrix of the body ply skim. In one or more embodiments, adhesion promoters of this nature may be formed by combining methylene donor compounds and methylene acceptor compounds within the rubber composition. Examples of methylene acceptor compounds include phenols, which include hydroxylated derivatives of arenes and equivalent compounds. Specific examples include monophenols, such as hydroxybenzene, bisphenols, polyphenols (polyhydroxyarenes), substituted phenols such as alkylphenols or aralkylphenols, for example bisphenols, diphenylolpropane, diphenylolmethane, naphthols, cresol, t- butylphenol, octylphenol, nonylphenol, xylenol, resorcinol, or analogous compounds. In other embodiments, methylene acceptor compounds include phenolic resins. Useful phenolic resins include novolac resins (a.k.a. novolak resins), which are also referred to as two-stage resins. Novolac resins may be formed from an acid-catalyzed condensation reaction between excess phenol and an aldehyde, particularly formaldehyde. Resorcinol- novolac resins include those novolac resins that include the acid-catalyzed reaction product of resorcinol and an aldehyde.

[0039] Examples of methylene donor compounds include those compounds that are capable of reacting with a methylene acceptor to form a methylene bridge. Examples of methylene donors include hexamethylenetetramine (HMT), hexamethoxymethylmelamine (HMMM or H3M), hexaethoxymethylmelamine, N-(substituted oxymethyl) melamine, formaldemelamine derivatives, or mixtures of these compounds. As is known in the art, the methylene donor can be delivered in conjunction with an inert carrier such as silica.

INGREDIENT AMOUNTS RUBBER

[0040] In one or more embodiments, the vulcanizable compositions include at least 20, in other embodiments at least 30, and in other embodiments at least 40 percent by weight of the rubber component, based upon the entire weight of the composition. In these or other embodiments, the vulcanizable compositions include at most 90, in other embodiments at most 70, and in other embodiments at most 60 percent by weight of the rubber component based on the entire weight of the composition. In one or more embodiments, the vulcanizable compositions include from about 20 to about 90, in other embodiments from about 30 to about 70, and in other embodiments from about 40 to about 60 percent by weight of the rubber component based upon the entire weight of the composition.

[0041] In one or more embodiments, the rubber component includes at least 50, in other embodiments at least 60, in other embodiments at least 70, and in other embodiments at least 80 percent by polychloroprene (e.g. polychloroprene homopolymer) based upon the entire weight of the rubber component. In these or other embodiments, the rubber component includes up to 100, in other embodiments at most 95, in other embodiments at most 90, and in other embodiments at most 85 percent by weight polychloroprene based upon the entire weight of the rubber component. In one or more embodiments, the rubber component includes from about 50 to about 100, in other embodiments from 60 to about 95, and in other embodiments from about 70 to about 90 percent by weight polychloroprene based upon the entire weight of the rubber component.

[0042] As suggested above, in certain embodiments of the invention, the rubber component includes (an in certain embodiments consists of) polychloroprene-based rubber (e.g. polychloroprene homopolymer) and natural rubber. In one or more of these embodiments, the weight ratio of polychloroprene to natural rubber may be from 0.5:1 to 7:1, in other embodiments from 1: 1 to 5.5: 1, and in other embodiments from 2:1 to 4.5:1. FILLER [0043] In one or more embodiments, the vulcanizable compositions include at least 25, in other embodiments at least 35, and in other embodiments at least 45 parts by weight (pbw) filler (e.g. carbon black) per 100 parts by weight rubber (phr). In these or other embodiments, the vulcanizable composition includes at most 120, in other embodiments at most 80, and in other embodiments at most 65 pbw of the filler phr. In one or more embodiments, the vulcanizable composition includes from about 25 to about 120, in other embodiments from about 35 to about 80, and in other embodiments from about 45 to about 65 pbw of filler phr. In one more embodiments, the filler component consists or consists essentially of carbon black.

PLASTICIZER

[0044] In one or more embodiments, the vulcanizable compositions include at least 1, in other embodiments at least 3, and in other embodiments at least 5 parts by weight (pbw) polychloroprene-specific plasticizer (e.g. sebacates) per 100 parts by weight rubber (phr). In these or other embodiments, the vulcanizable composition includes at most 20, in other embodiments at most 15, and in other embodiments at most 12 pbw of the polychloroprene-specific plasticizer phr. In one or more embodiments, the vulcanizable composition includes from about 1 to about 20, in other embodiments from about 3 to about 15, and in other embodiments from about 5 to about 12 pbw of polychloroprene- specific plasticizer phr.

ANTIDEGRADANTS

[0045] In one or more embodiments, the vulcanizable compositions of this invention include at least 3, in other embodiments at least 5, in other embodiments at least 7 parts by weight (pbw) total antidegradant (e.g. antioxidant and/or antiozonant) per 100 parts by weight rubber (phr). In these or other embodiments, the vulcanizable composition includes at most 20, in other embodiments at most 15, and in other embodiments at most 12 pbw total antidegradant phr. In one or more embodiments, the vulcanizable composition includes from about 3 to about 20, in other embodiments from about 5 to about 15, and in other embodiments from about 7 to about 12 pbw total antidegradant phr. OIL

[0046] In one or more embodiments, the vulcanizable compositions of this invention include at least 1, in other embodiments at least 2, in other embodiments at least 3 parts by weight (pbw) total oil per 100 parts by weight rubber (phr). In these or other embodiments, the vulcanizable composition includes at most 15, in other embodiments at most 12, and in other embodiments at most 10 pbw total oil phr. In one or more embodiments, the vulcanizable composition includes from about 1 to about 15, in other embodiments from about 2 to about 12, and in other embodiments from about 3 to about 10 pbw total oil phr.

CORD ADHESION PROMOTOR

[0047] In one or more embodiments, the vulcanizable compositions of this invention include at least 0.01, in other embodiments at least 0.1, in other embodiments at least 0.5 parts by weight (pbw) total cord adhesion promotor per 100 parts by weight rubber (phr). In these or other embodiments, the vulcanizable composition includes at most 5, in other embodiments at most 3, and in other embodiments at most 1.5 pbw total cord adhesion promotor phr. In one or more embodiments, the vulcanizable composition includes from about 0.01 to about 5, in other embodiments from about 0.1 to about 3, and in other embodiments from about 0.5 to about 1.5 pbw total cord adhesion promotor phr.

CURE SYSTEM

[0048] The skilled person will be able to readily select the amount of vulcanizing agents to achieve the level of desired cure. Also, the skilled person will be able to readily select the amount of cure accelerators to achieve the level of desired cure.

MIXING PROCEDURE

[0049] The vulcanizable compositions employed in the practice of this invention may be prepared by using conventional techniques for preparing vulcanizable compositions. For example, all ingredients of the rubber compositions can be mixed with standard mixing equipment such as Banbury or Brabender mixers, extruders, kneaders, and two-rolled mills. In one or more embodiments, the ingredients are mixed in two or more stages. In the first stage (i.e., mixing stage), which typically includes the rubber component and filler, is prepared. To prevent premature vulcanization (also known as scorch), vulcanizing agents. Once the masterbatch is prepared, the vulcanizing agents may be introduced and mixed into the masterbatch in a final mixing stage, which is typically conducted at relatively low temperatures so as to reduce the chances of premature vulcanization. Additional mixing stages, sometimes called remills, can be employed between the masterbatch mixing stage and the final mixing stage.

PREPARATION OF TIRE

[0050] The vulcanizable compositions employed in this invention can be processed into the identified tire components according to ordinary tire manufacturing techniques including standard rubber shaping, molding and curing techniques.

[0051] In practice of the present invention, those tire components that are not prepared from the vulcanizable compositions discussed herein (e.g. the tread or bead filler) can be prepared in a conventional or known manner. In one or more embodiments, the tread package and bead fillers are prepared from vulcanizable compositions that are different than the vulcanizable composition used to prepare the skim rubber, innerliner, sidewalls, and abrasion strip. The skilled person can readily prepare a vulcanizable compositions that are useful for preparing various tire components, such as the tread components, without undue experimentation or calculation. These components that then be combined with the components prepared using the vulcanizable compositions discussed herein to form a green tire that can then be cured.

[0052] Pneumatic tires can be made as discussed in U.S. Patent Nos. 5,866,171, 5,876,527, 5,931,211, and 5,971,046, which are incorporated herein by reference. For example, the various tire components can be prepared as green tire components (i.e., uncured tire components), and assembled into a green tire. The green tire can then be subjected to curing conditions to form a vulcanized tire wherein the various green components are generally adhered to one another through the vulcanization process.

[0053] Typically, vulcanization is effected by heating the vulcanizable composition in a mold; e.g., it may be heated to about 140 °C to about 180 °C. Cured or crosslinked rubber compositions may be referred to as vulcanizates, which generally contain three- dimensional polymeric networks that are thermoset. The other ingredients, such as fillers and processing aids, may be evenly dispersed throughout the crosslinked network. In particular embodiments, one or more of the compound ingredients may become crosslinked or otherwise chemically bonded to the crosslinked rubber network. As the skilled person will appreciate, the amounts of the various ingredients, especially those that do not react, will remain within the cured tire component the same as they existed within the compound.

[0054] In order to demonstrate the practice of the present invention, the following examples have been prepared and tested. The examples should not, however, be viewed as limiting the scope of the invention. The claims will serve to define the invention.

EXPERIMENTAL SECTION

[0055] In order to demonstrate the advantages of the present invention, three vulcanizable compositions were prepared. The compositions were cured and tested for various properties to assess their usefulness as a sidewall, inneriiner, body ply skim rubber, and abrasion strip within a tire. The recipes for the various compositions are set forth in Table I.

Table I

Compound Compound Compound

INGREDIENTS

1 2 3

MASTERBATCH

Natural Rubber 20 60 20

Polychloroprene 80 - -

Polybutadine - 40 -

Butyl Rubber - - 80

Carbon Black 55 55 55

Stearic Acid 0.5 1.5 2.0

MgO 4.0 - 0.2

ZnO - 2.5 -

Oil 5.0 15 12

6PPD 4.0 2.5 -

TMQ 2.0 2.0 -

Wax 2.0 2.0 -

Plasticizer 8.0 - -

FINAL

ZnO 5.0 - 3.0

Sulfur 1.25 1.5 0.5

TMTM 0.5 - -

TMQ 2.0 - -

TBBS - 1.0 -

MBTS - - 1.3

DAY OF CURING

12/08/2014 MH 15.26 12.33 8.56

ML 3.16 1.94 2.28

MH-ML 12.1 10.39 6.28

T50 5.52 5.08 7.39

T90 15.92 7.06 14.31

DAY OF MIXING

11/25/2014

MH 14.25 12.55 8.43

ML 1.59 1.94 2.25

MH-ML 12.66 10.61 6.18

T50 6.42 4.78 7.29

T90 15.9 6.68 14.25

[0056] As suggested in Table I, the vulcanizable compositions were prepared by using a two-step mixing technique (i.e. Masterbatch and Final). With the first step (Masterbatch), the masterbatch ingredients were mixed to a drop temperature of about 155 °C. The composition was then cooled and the curative package was added. Mixing was then continued (Final step) to a drop temperature of about 140 °C.

[0057] Table I also provides Rheometer data for each composition as measured on the day the composition was prepared and the day on which the composition was ultimately cured, which was about two weeks after initial preparation. This Rheometer data establishes that these compositions would be useful in the tire manufacturing process. Rheometer testing was conducted using a MDR 2000 Rheometer (Alpha Technologies).

[0058] Samples of these three compositions were employed to prepare various test specimens that were analyzed in order to assess the usefulness of the various compositions for preparing sidewalls, innerliners, body ply skim rubber, and abrasion strips for pneumatic tires. In conducting these tests, multiple cure conditions were employed. In the first instance, each of the three vulcanizable compositions were cured using the same cure conditions. In a second set of experiments, the cure conditions were tailored to employ cure conditions that are generally conventional for the type of composition employed. The cure conditions and the results of the various testing that was conducted is set forth in Table II. Table II

[0059] Dynamic Ozone testing was conducted by employing a Satra/Hampden Ozone 703 Chamber. As noted in the Table, testing was conducted at 0 °C and 30 °C for twenty- four hours. Static Ozone testing was conducted within an OREC Ozone Monitor according to ASTM D-1149 for 7 days at 60 °C. Bent Loop Ozone testing was conducted within an OREC Ozone Monitor according to ASTM D-1149 for 7 days at 60 °C. Color was determined by employing a Minolta CM2600D Spectrophotometer, calibrated according to the manufacturer's standards. Mocon Air Permeability was determined by using MOCON OX- TRAN 2161 monitor. Cord Pull Through was determined according to standard procedure. Fatigue to Failure was determined according to ASTM D-4482. PICO Abrasion was determined according to ASTM D-2228-83. Mechanical Properties were determined according to ASTM D-412.

[0060] Various modifications and alterations that do not depart from the scope and spirit of this invention will become apparent to those skilled in the art. This invention is not to be duly limited to the illustrative embodiments set forth herein.

Claims

CLAIMS What is claimed is:

1. A pneumatic tire comprising:

a. a carcass including a skim rubber;

b. a pair of sidewalls;

c. a pair of bead bundles;

d. a pair of abrasion strips; and

e. a tread, where the skim rubber, the sidewalls, and the abrasion strips are compositionally similar.

2. The pneumatic tire of claim 1, where the pneumatic tire further includes an innerliner, and where the skim rubber, the sidewalls, the abrasion strips, and innerliner are compositionally similar.

The pneumatic tire of any one or more of the preceding claims, where the skim rubber, the sidewalls, the abrasion strips, and optionally innerliner are prepared from a vulcanizable composition including a rubber component that includes a polychloroprene-based elastomer.

The pneumatic tire of any one or more of the preceding claims, where the skim rubber, the sidewalls, the abrasion strips, and optionally innerliner are prepared from a vulcanizable composition including a rubber component that includes a polychloroprene-based elastomer and natural rubber.

The pneumatic tire of any one or more of the preceding claims, where the skim rubber, the sidewalls, the abrasion strips, and optionally innerliner are prepared from a vulcanizable composition including (i) a rubber component that includes a polychloroprene-based elastomer and natural rubber, (ii) a filler, (iii) a plasticizer, and (iv) a curative.

6. The pneumatic tire of any one or more of the preceding claims, where the skim rubber, the sidewalls, the abrasion strips, and optionally innerliner are prepared from a vulcanizable composition including a rubber component that includes a polychloroprene-based elastomer and natural rubber, and where the weight ratio of polychloroprene-based elastomer and natural rubber is from about 0.5:1 to about 7:1.

7. The pneumatic tire of any one or more of claims 5-6, where the filler is carbon black.

8. The pneumatic tire of any one or more of claims 3-7, where the vulcanizable composition includes from about 25 to about 120 parts by weight carbon black per 100 parts by weight rubber.

9. The pneumatic tire of any one or more of claims 3-8, where the vulcanizable composition includes at least 50 percent by weight polychloroprene based upon the entire weight of the rubber component.

10. The pneumatic tire of any one or more of claims 3-9, where the vulcanizable composition includes at least 60 percent by weight polychloroprene based upon the entire weight of the rubber component.

11. The pneumatic tire of any one or more of claims 3-10, where the vulcanizable composition includes at least 70 percent by weight polychloroprene based upon the entire weight of the rubber component.

12. A pneumatic tire comprising:

a. a carcass including a skim rubber;

b. a pair of sidewalls;

c. a pair of bead bundles;

d. a pair of abrasion strips; and e. a tread, where the skim rubber, the sidewalls, and the abrasion strips are prepared from a single vulcanizable composition that includes a rubber component including a polychloroprene-based rubber.

13. The pneumatic tire of claim 12, where the pneumatic tire further includes an innerliner, and where the skim rubber, the sidewalls, the abrasion strips, and innerliner are prepared from a single vulcanizable composition that includes a rubber component including a polychloroprene-based rubber.

14. The pneumatic tire of any one or more of claims 12-13, where the rubber component further includes natural rubber.

15. The pneumatic tire of any one or more of claims 12-14, where the vulcanizable composition includes (i) a rubber component that includes a polychloroprene-based elastomer and natural rubber, (ii) a filler, (iii) a plasticizer, and (iv) a curative.

16. The pneumatic tire of any one or more of claims 12-15, where the vulcanizable composition includes a rubber component that includes a polychloroprene-based elastomer and natural rubber, and where the weight ratio of polychloroprene-based elastomer and natural rubber is from about 0.5:1 to about 7: 1.

17. The pneumatic tire of any one or more of claims 15-16, where the filler is carbon black.

18. The pneumatic tire of any one or more of claims 12-17, where the vulcanizable composition includes from about 25 to about 120 parts by weight carbon black per 100 parts by weight rubber.

19. The pneumatic tire of any one or more of claims 12-18, where the vulcanizable composition includes at least 50 percent by weight polychloroprene based upon the entire weight of the rubber component.

20. The pneumatic tire of any one or more of claims 12-19, where the vulcanizable composition includes at least 60 percent by weight polychloroprene based upon the entire weight of the rubber component.

21. The pneumatic tire of any one or more of claims 12-20, where the vulcanizable composition includes at least 70 percent by weight polychloroprene based upon the entire weight of the rubber component.

22. A method for preparing a pneumatic tire, the method comprising the steps of:

a. preparing a vulcanizable composition including a rubber component that includes polychloroprene;

b. forming the vulcanizable composition into tire components that include a carcass, a pair of sidewalls, and a pair of abrasion strips;

c. building a green tire from the tire components; and

d. curing the green tire to form the pneumatic tire.

23. The method of claim 22, where the tire components further include an innerliner.

24. The method of any one or more of claims 22-23, where the rubber component further includes natural rubber.

25. The method of any one or more of claims 22-24, where the vulcanizable composition includes (i) a rubber component that includes a polychloroprene-based elastomer and natural rubber, (ii) a filler, (iii) a plasticizer, and (iv) a curative.

26. The method of any one or more of claims 22-25, where the vulcanizable composition includes a rubber component that includes a polychloroprene-based elastomer and natural rubber, and where the weight ratio of polychloroprene-based elastomer and natural rubber is from about 0.5:1 to about 7: 1. The method of any one or more of claims 25-26, where the filler is carbon black.

The method of any one or more of claims 22-27, where the vulcanizable composition includes from about 25 to about 120 parts by weight carbon black per 100 parts by weight rubber.

The method of any one or more of claims 22-28, where the vulcanizable composition includes at least 50 percent by weight polychloroprene based upon the entire weight of the rubber component.

The method of any one or more of claims 22-29, where the vulcanizable composition includes at least 60 percent by weight polychloroprene based upon the entire weight of the rubber component.

The method of any one or more of claims 22-30, where the vulcanizable composition includes at least 70 percent by weight polychloroprene based upon the entire weight of the rubber component.